Selector signaling system



(No Model.) 7 J T. G. DRAKE.

SELECTOR SIGNALING SYSTEM.

No. 605,688. PatentedJune 14,1898.

ME ll Witnesses 7/ Inventor,

UN TED STA PATENT @rrron;

THOMAS o. DRAKE, or MALTA, OHIO.

' V SELECTOR SIGNALING SYSTEM.

SPECIFICATION forming part of Letters Patent No, 605,688, dated June 14, 1898.

Application filed September 17, 1897. Serial No. 652,017. (No model.)

To all whom it nrly concern;

Be it known that I, THOMAS C. DRAKE, a citizen of the United States, residing at Malta, in the county of Morgan and State of ,Ohio, have invented a new and useful Improvement in Electric Selector Systems and Apparatus, of which the following is a specification.

My invention relates to an improvement in selector signaling systems and apparatus to be used in connection with telephones or any signaling service requiring individual or $6- lective signaling properties. 7

It is an improvement upon the mechanisms and system which are the subject of applications filed July 2, l894t,Serial.No. 516,355, and February 26, 1897, SerialNo. 625,230;

The line of invention presented in the above-mentioned applications and this present one pertains to a system and mechanisms of the step-by-step and restoring variety..

This series of applications describe mechanisms which are designed to be operated in series in a proper circuit witha suitable source of current, such as a constant battery.

The particular features presented in the system and mechanisms are, first, to operatea comparatively large number of stations on one circuit in such a manner that any station can call a selected station without disturbing or operating the alarm apparatus of the stations not desired; second, a form of mechanism which will remain in unison and retain a sure operating relation to one another; third, a mode of operation which admits of stepping the revolving parts of every mechanism in unison to a predetermined position and returning the revolving parts to normal position from anyone and all stations in the circuit; fourth,-a mechanism which will revolve suitable contact-disks to the requisite position on passing an intermittent current through the operating electromagnets and return the contact-disks to their normal or starting position on passing a current of the normal current strength may be diminished and made intermittent to operate the step-by-step mechanism in one instance and the normal current restored in thecircuit to operate the restoring mechanism in another.

The improvements relate to anew form of mechanism which obviates contingencies existing in step-by-step and restoring mechanisms of this class and also to a combination and arrangement of circuits, resistances, and relays by means of which the mechanisms are more perfectly and satisfactorily operated than heretofore. I

In the applications mentioned above the mechanisms therein shown and described are constructed to operate with one set of electromagnets, the operation of the mechanisms being such as to step the ratchet-Wheel and contact-disk under the influence of the diminished current by a combination of levers and stress-springs and reset the ratchet-Wheel and contact-disk to normal position on passing the normal current, which overcomes the stress-springs and operates the lovers in a different manner to disengage the pawls.

In the improved mechanismhereindescribed the step-by-step mechanisms and the restoring mechanisms are operated by an electromagnet for each, the two electromagnets being series or parallel, connected so that the diminished current mayoperate the step-by-step mechanisms and the normal current may operate the restoring mechanisms respectively.

In the accompanying drawings," Figure 1 represents an elevation of the mechanism and operating-circuits; Fig. 2, an enlarged elevation of a part of the stepping mechanism, showing the pawl-locking arrangement here 'inafter described; Fig. 3, a diagrammatic view showing a relay-battery cut-out which may be substituted fora similar arrangement in the system.

The mechanisms, as will be described in detail farther on, are so constructed that by passing a current of given strength intermittently through the circuit in which they'are contained they will operate in unison to step the ratchet-wheels and contact-disks,and by passing a current of greater strength through the circuit the mechanism will operate in unison to restore the ratchet-wheels and contactdisks to their normal or starting position.

To more clearly understand the practical working of the mechanism, suppose With the proper v-inding on themagnets ten milliam pores of current are passed intermittently through the circuit. This we assume to work the step-by-step mechanism. By suitable means fifteen milliamperes of current are passed through the circuit. This we assume to operate the restoring mechanism, which returns the revolving parts to normal position.

The mechanism is constructed as follows:

Mounted on the shaft 1 is a ratchet-wheel 2, containing as many or more teeth than there are instruments in the system, also a commutator or contact-disk 3, constructed by placing a band or rim of insulating material around the periphery of a metallic disk. A contact 10 passes through the insulated band and forms a metallic segment on the periphery of the disk. A pinion-gear 1, (represented by the dotted circles,) meshing with the weighted segment-gear 5, serves to return the ratchet-wheel and contact-disk to normal or starting position on the disengagement of the pawls 15 and 16, as will be hereinafter explained. The shaft 12 carries a lever 13, on one end of which is mounted an armature 17 and on the other two pawls 15 and 16. This arrangement of pawls is used in order to get a double step of the ratchet-wheel at each impulse of current. By applying both the outward and return movements of the lever 13 to stepping the ratchet-wheel the oscillat ing distance of armature 17 is diminished to one-half that which would be required if only one stepping-pawl was used, and the energy necessary to operate the mechanism is also proportionately diminished. However, the ordinary arrangement of pawls, in which there is one stepping-pawl and one click, may be substituted for this arrangement and the bifurcated lever 18 adapted to disengage them, substantially as shown. The bifurcated lever 18, mounted on a shaft 19, carries an armature which is actuated by electromagnet M. A pin 0, which extends under the pawl 15, and the formed end D of the long arm of lever 18 are to lift the pawls out of engagement with the ratchet.

Limiting and adjusting screws 21 and are to adjust the pawls to the ratchet, the former limiting the outward movement of lever 13 and the latter forming a contact-point for the contact-disk segment and adjusting the return movement by coming in contact with the periphery of the contact-disk. The contact-screw is insulated from the lever 13 byinsulating-bushing 23 and has electrical connection with spring adjustment 25 by means of spring-wire 24, which is also insulated at the point HQ.

The restoring mechanism hereinbeforc men tioned consists of the electromagnet M, which lifts the bifurcated lever 18 on the passing of the normal current. The lever 18 disengages the pawls 15 and 1(3, whereupon the weighted segment-gear 5 returns the ratchet-wh eel and contact-disk to zero or normal position.

The step-by-step mechanism hereinbefore mentioned consists of the electromagnet M,

the lever 13, the pawls 15 and 1G, and the ratchet-wheel and armature. The magnet M oscillates the lever 13 under the impulses of the diminished intermittent current to step the contact-segment of the disk into position to make contact with the contact-screw 22, whereupon the circuit C is closed in multiple with the ground through the auxiliary signaling apparatus. The auxiliary signaling apparatus is diagramed in symbol at each station and will be described more fully later 011.

In the ordinary or more common forms of stcp-by-step mechanisms no means are provided by which the momentum of the ratchetwheel and other revolving parts may be kept from carrying the ratchet in advance of the movement of the pawls, which impairs the accuracy of the mechanism to work in unison. To avert this contingency is a special feature of my improved mechanism, and it may be substantially combined with the construction shown in my applications hereinbefore mentioned. This feature of the mechanism opcrates as follows: The pins A and C are a rigid part of the lever 18, and, as hereinbefore explained, the lever 18 lifts the pawls 15 and 16 out of engagement with the ratchet. The pin 0 extends under and the pin A over the pawl 15. The pawl 15 is shaped with an incline protuberance 13, the angle of which frees the pin A and admits the pawls engagin g the ratchet during the oscillation of lever 13. As the lever 13 oscillates to step the ratchet and reaches the adjusting-screw 21 in its outward movement the inclined protuberance of pawl 15 is brought under the pin A in such a manner as to hold the pawl in the tooth of the ratchet, so as to overcome the momentum of the revolving parts. This pin prevents the pawl from moving u pward,which would permit one or more teeth to pass under the hooked end, thereby deranging the synchronous rotation of the contact-disks.

The supplemental circuit C is diagrammed with ground return in order to be easily distinguished from the step-by-step circuit C, as the two circuits are not electrically connected in any way. The grounds are represented by the ordinary symbols.

The circuit C is normally on open circuit, and the step-by-step circuit C is normally on closed circuit.

The supplemental circuit C, which might be designated as a ringing and talking circuit from the fact that it serves in that capacity as well as a supplemental circuit to operate the relay I, connects the ringing and talking apparatus as well as the contact-disk portion of the station mechanism in open circuit with the groundthat is to say, the circuit C is legged to the ground at-each mechanism, the leg passing through the ringing and talking apparatus and connecting to the contact-disk and framework of the mechanism, the frame of the mechanism and contactdisk in turn being grounded at the will of the operator through the instrumentality of the contact-screw 22,which is normally grounded, and also the switch F, which is diagrammed to ground the supplemental circuit 0 when in a released position.

The contact-screw 22 is insulated from the framework of the mechanism by insulatingbushing 23 and is normally in electrical connection with grounded spring adjustment 25 by retractile spring 24.

It is understood from the construction of the mechanism'that the contact-disk 3 is insulated from the contact-screw 22 by a band connect the terminals of the step-by-step circuit O, and when in a released position is understood to connect the terminals of the circuit C. The switch, therefore, when in normal position leaves the supplemental circuit O on normally open circuit at each station and the step-by-step circuit C on normally closed circuit.

The office of the relay I, which is in the circuit O and normally grounded through the battery E, is to cut in and cut out of the circuit C the resistance R. The function of the resistance will be hereinafter more fully explained.

As the circuit C is normally open at all the contact disks and switches, it is obvious that the battery E will not energize the relay, and therefore the armature will stand in contact with K, which cuts the resistance R out of the circuit C; but if the circuit C is closed by releasing any one of the switches F the relay is energized by the battery E, whereupon the continuity of the step-by-step circuit C is made to pass through the resistance R by reason of the armature assuming contact with contact-screw K.

As hereinbefore described, the restoring mechanismi. e., that which disengages the pawls 15 and 16 in order that the weighted segment-gear 5 may reset the contact-disks and ratchet-wheels to zero or normal positionis operated by the normal current from the battery H, which passes through the circuit O continuously, except when one of the switches F is released. As before stated, when one of the switches is released the circuit O is grounded or closed through the relay I, which in turn throws the resistance R into the circuit C, whereupon the normal current from battery H is diminished in strength. This diminished strength of current, as before stated, operates the step-by-step mechanism on being passed intermittently through the circuit O-t'. e., at each pulsation of the diminished current the lever 13 is oscillated to stepthe ratchet-wheel 2 by'the electromagnet M and the retractile spring 24. The make-and-break contact-crank G serves to pulsate the diminished current, the switch F,

when down, keeping it on short circuit, so as to maintain the continuity of the circuit C.

The function of the relayI is to simply diminish the normal intensity of current flowing from the battery 11 through the step-bystep circuit at the instant it is desired to make a call from one station to another. The magnetic coil in the relay is preferably wound to,

high resistance and constructed to have high impedance in order that the currents generated in the ringing and talking apparatus will not pass through it to any appreciable amount when connected in multiple with it. It is already understood that the ringing and talking auxiliary apparatus is connected in open multiple with the circuit C and the ground and that the relay is continually grounded on this circuit, so as to be operated whenever any one of the switches are released.

It is well understood in the art how high-resistance and high-impedance coils keep the talking and ringing currents out and forces them through lower resistance and impedance coils when connected in a multiple or bridging system.

The resistance is a simple, practical, and preferable means by which to diminish the normal current; but other means may be employed. Fig. 3 shows how the battery may be divided and all or a, section thrown on the step-by-step circuit. When the relay is not energized, the armature cuts in all the battery and when energized cuts off a portion.

One terminal of the step-by-step circuit, in which is the operating-battery H, is connected to the relay-armature and the other terminal to contact-screw K. The resistance or other means employed to diminish the normal current is connected across the contacts K and K. On releasing any one of the switches F the supplemental circuit C is grounded or closed through the relay I, which operates to decrease the strength of the normal current by placing the resistance R or other means in the step-by-step circuit 0.

Each step-by-step and restoring mechanism is operated by means of two distinct electromagnets. These magnets may be connected either in series or parallel with equal results in either case. The electromagnet M steps the ratchet-wheel on passing the diminished intermittent current, and the electromagnet M disengages the pawls '15 and 16 by means of lever 18 on passing the normal current. The diminished current herein referred to will not give sufficient magnetic strength to magnet M to operate the lever 18. Therefore there will be'no inclination during the passing of the intermittent current to disengage ICC IIO

the pawls;-but the normal current which 7 to make contact with the contact-screw 22 at a predetermined point of revolution of shaft 1. The contact-disk is adjustably mounted on said shaft, so that each may be set to a different position in respect to the normal or zero position of the system. Each mechanism requires a different and distinct number of steps to bring the contact-disk into position to close the circuit C to the ground, so that a signal may be sent to any selected instrument, respectively.

The operation of the system is as follows: To make a call from one station to another, the switch F is released, which opens the step-bystep circuit C and grounds the supplemental circuit C through the relay I. The relay I in return throws the relay-armature to contact K, whereupon the resistance R is cut in the step-by-step circuit to diminish the normal current. On revolving the contactcrank G the diminished current is passed intermittently through the step-by-step mechanism. The electromagnet M is adjusted and adapted to oscillate the lever 13 under the influence of the diminished intermittent current, while the magnet M is adjusted to operate the lever 18 under the influence of the normal current only. As before stated, the contact-disk at each mechanism is set to close the circuit C at different points of revolution of the contactdisk, so that to throw in a selected station requires the contact-segment 10 of the disk at the station selected to be stopped opposite the contact-screw 22, where upon t-he circuit C is grounded through the signaling auxiliary apparatus at that station on leaving the step-by-step circuit open. On completion of the call the switches F are returned to their normal position, which is in contact with circuit C. This operation closes the step-by-step circuit and opens the supplemental circuit O'. On opening the circuit C the armature of relay 1 is released,whereupon the resistance is cut out and the normal current restored in circuit C. On restoring the normal current the magnets M are given strength enough to operate the levers l8,which disengage the pawls 15 and 16, whereupon the ratchet-wheels and contact-disks are returned to normal orstartingposit-ion by the weighted segment-gear 5.

In the system shown and described in the applications filed July 2, 1894:, Serial No. 516,355, and February 20, 1807, Serial No. 625,230, the resistances employed to diminish the normal current are arranged one at each instrument or station, the resistances being equivalents to each other. To diminish the normal current necessitates the resistance at the station making the call to be cut into circuit, whereupon the contact-disks are stepped into position on pulsating the current. The

restoring mechanisms.

supplemental circuit and relay with one resistance, as is diagramed in Fig. 1, any change in the normal resistance of the circuit may be compensated for and the proportion between the normal and the diminished current maintained by means of an adjustable battery and adjustable resistance, whereas in case of a resistance at each mechanism or station an adjustment of each and every one would be necessary.

The plan of cutting off and on a section of battery, as shown in Fig. 3, is a simple and effectual method of varying the strength of current in the circuit to operate the system as herein described. It, however, necessitates the relay being in direct connection with the battery and the supplemental circuit extending to the relay in order to operate the same, whereas by the use of one resistance, as herein diagramed, the relay may be installed at any convenient point in the system.

Having described my invention, I desire to claim and secure by Letters Patent as follows:

l. The combination in a selector system, of a line-circuit connecting a series of step-bystep and restoring mechanisms at a series of stations respectively, means for moving the series of step-by-step mechanisms to a predetermined position by an intermittent current, and means for operating the series of restoring mechanisms to reset the series of step-bystep mechanisms to normal 011 passinga current of greater strength than said intermittentcurrent, the stepping and restoring mechanisms comprising the electromagnets M, and M, connected in said line-circuit whereby said diminished current may operate the ratchetwheel, lever and pawls to rotate the contact-disk, and the normal current may operate the bifurcated lever to disengage the pawls respectively, the contact-disk and contact-screw to close a signaling-circuit at a predetermined position of rotation of said series of mechanisms, and the segment-gear to rcturn the ratchet-wheel and contact-disk to normal position on operating the restoring mechanism to reset the system.

2. The combination in a selector system of a line-circuit connecting a series of step-bystep and restoring mechanisms at a series of stations respectively, means for moving the series of step-by-step mechanisms to a predetermined position by an intermittent current, and means for operating the series of restoring mechanisms to reset the series of step-bystep mechanisms to normal on passing a current of greater strength than said intermittent current, the stepping and restoring mechanisms comprising the ratchet-wheel, lever and pawls to rotate the contact-disk, the contact-disk and contact-screw to close the signaling-circuit at a predetermined position of rotation of said series of mechanisms, the pawl with protuberance B, acting with the stop-pin A, whereby the said pawl is locked into the teeth of said ratchet-wheel to check the momentum of the said ratchet-Wheel and contact-disk, the bifurcated lever operated by said normal current to disengage the pawls, and the segment-gear to return the ratchetwheel and contact-disk to'normal position on operating the restoring mechanism to reset thesystem.

3. In a selector step-by-step and restoring mechanism, the combination of the ratchetwheel and contact-disk, the pawls, lever and electromagnet M, to step the ratchet-wheel and-contact-disk, the bifurcated lever 18, and electromagnet M to disengage the pawls, the weighted segment-gear and pinion-gear to return the ratchet and contact-disk to normal position, the contact-disk and contact-screw 22, to close the circuit through the auxiliary signaling devices, and the means to check the momentum of the ratchet and contact-disk which consists of the pawl 15, with the protuberance B, operating in relation with the pin A, carried by the bifurcated lever 18, whereby the said pawl is locked into the teeth of said ratchet, substantially as specified.

4. In a selector system, the combination of a series of mechanisms connected by a linecircuit, a battery and switches located in said line-circuit, a supplemental circuit connected to each of said mechanisms or switches, a current-controlling relay located in said supplemental circuit and adapted to diminish the normal current through said line-circuit when said switches are in position to close said supplemental circuit, and to pass the normal current through said line-circuit when said switches are in position to leave said supplemental circuit open, means at each mech anism to pulsate said diminished current through the series of mechanisms, said mechanisms adapted to be synchronously stepped to a predetermined position by the diminished intermittent current, and synchronously restored to normal position by the said normal current.

5. The combination in a selector system, of a line-circuit connecting a series of step-bystep and restoring mechanisms at a series of stations respectively, an operating-battery located in said circuit,a series of contact-cranks, and a series of switches located at said stations by means of which the said line-circuit may be opened and closed and the current pulsated through the step-by-step mechanism, a supplemental circuit connected to each of said mechanisms or switches,abattery-controlling relay with its operating-battery located in said supplemental circuit by means of which the normal current in the line-circuit may be diminished when it is desired to step the mechanisms and restored when it is desired to restore the mechanisms, the stepby-step and restoring mechanisms comprising the ratchet-wheel, lever and pawls to rotate the contact-disk, the contact-disk and contact-screw to close the signaling-circuit at a predetermined posit-ion of rotation of said series of mechanisms, the bifurcated lever op erated by the said normal current to disengage the pawls, and the segment-gear to re- 1 turn the ratchet-wheel and contact-disk to normal position on operating the restoring mechanism to reset the system.

6. In a selector step-by-step and restoring system the combination of a station apparatus consisting of the ratchet-wheel and contact-disk the pawls and lever operated by the electromagnet M to step the said ratchet and contact-disk, the contact-disk and contactscrew 22 to closethe circuit C, the bifurcated lever 18 operated by the electromagnet M to disengage the pawls, the pinion-gear and segment-gear to return the ratchet and contactdisk to normal position, the means of checking the momentum of the ratchet-wheel consisting ofthe pawl 15 with the protuberance B operating with the pin A carried by the lever 18, the contact-crank to pulsate the current through the system, and the switch F to normally close the circuit C.

THOMAS C. DRAKE.

Witnesses:

JOHN D. ERWIN, GEO. M. Soorr. 

